Opaque mat with diamond pattern



FIG. 1 is a top plan view of the opaque mat with diamond pattern;

FIG. 2 is a side profile view thereof; the left side of the figure being representative of the top plan view of FIG. 1;

FIG. 3 is an enlarged detail view of area 3 circumscribed within or on FIG. 2; and,

FIG. 4 is an enlarged detail view of area 4 circumscribed within or on FIG. 1.

The portions of the opaque mat with diamond pattern shown in broken lines form no part of the claimed design. 

CLAIM The ornamental design for an opaque mat with diamond pattern, as shown and described. 